Introduction
This “Universal Static Transfer Switch” (USTS), is a Single Pole (Neutrals Common)
automatic static transfer switching unit designed to provide fast automatic
transfers between two independent, synchronous or asynchronous AC power
sources to provide continuity of AC power to critical equipment, such as
information technology equipment, process control equipment, etc.
One of the two AC inputs is designed as the “preferred” source to which the USTS
will connect the load as long as the designated input source is within the
acceptable limits, the USTS is designed to transfer the output load to the
alternate input source, if the alternate source is within provides the acceptable
voltage limits.
The USTS fast, Make-before-break transfers, between the two sources and prevents
interphase currents during transfers between the two sources.
The control circuitry ensures that the transfer time is within the tolerance of IEEE
Standard 446 susceptibility curve for Information Technology Equipment to allow uninterrupted
load equipment operation.
In case of overload and phase shift the USTS gives indication only on front panel.
Green colour indicates healthy condition and Red colour is for out of range condition.
Under Short-circuit condition the fuses in series with the Sources protect source
and the load.
Manual Bypass Switch:
The entire power static switch module is hot swappable. Before removing this
module the load is transferred, without break to any one of the sources by using
the Manual bypass switch, which is of Make before Break type. After replacing
the static switch module, the load is restored on static switch module, using the
Manual bypass switch.
